Detailed Measurements of a Diffusive Supersonic Wave in a Radiatively Heated Foam

Back, C. A.; Bauer, J. D.; Landen, O. L.; Turner, R. E.; Lasinski, B. F.; Hammer, J. H.; Rosen, M. D.; Suter, L. J.; Hsing, Wen Hao

doi:10.1103/physrevlett.84.274

Cited by 58 publications

(49 citation statements)

References 15 publications

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“…Low-density material foam~Basko & Meyer-ter-Vehn, 1993; Borisenko et al, 2003;Philippe et al, 2004! has come to play an important role as an efficient converter and hence, many experiments were done on supersonic heat wave propagation in foam Afshar-rad et al, 1994;Massen et al, 1994;Back et al, 2000aBack et al, , 2000b!. Usually, it was assumed that the photons begin to thermalize at about one optical depth, that is, the emission is isotropic and the spectrum is in planckian distribution, so the diffusive approximation begins to be applicable.…”

Section: Introductionmentioning

confidence: 99%

Study on two-dimensional transfer of radiative heating wave

et al. 2005

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A two-dimensional~2D! multigroup radiation transfer hydrodynamics code LARED-R-1 is used to simulate a supersonic wave experiment performed earlier by the Livermore group. The main result is that, contrary to the conclusion of Back et al.~2000a!, the average-atom opacity model is sufficient to explain the obtained experimental results, provided that an adequate description of the radiation transport was used. The simulation results from LARED-R-1 show the spectrum of radiation in foam with radius and length of several optical depths is not in Planckian distribution and the angular intensity distribution is anisotropic.

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Section: Introductionmentioning

confidence: 99%

Study on two-dimensional transfer of radiative heating wave

et al. 2005

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“…Recently, some laboratories have observed propagation of thermal radiation in optically thick and thin sample [1][2][3][4][5][6][7][8][9][10]. The diffusive and supersonic x-ray transport in the radiatively heated foam was detailedly measured [2][3][4][5][6][7]. Although the transport delay time of a certain photon group with in thermal radiation has been investigated [4,5], the transport velocities of the photon groups with different energies in foam are different, because their opacities vary with photon energy.…”

Section: Introductionmentioning

confidence: 99%

“…The diffusive and supersonic x-ray transport in the radiatively heated foam was detailedly measured [2][3][4][5][6][7]. Although the transport delay time of a certain photon group with in thermal radiation has been investigated [4,5], the transport velocities of the photon groups with different energies in foam are different, because their opacities vary with photon energy. Additional, the properties of radiation source used to heat foam sample was important, and the planar distribution of the source need to investigate.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation of diffusive supersonic radiation propagation in low density CH foam doped with Cu

et al. 2004

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Eight beams of 0.35 mm laser with pulse duration of 1ns and 2 kJ of total energy enter into a hohlraum to create intense x-ray radiation on the Shenguang II laser facility. The plastic foam doped with 59 nanometers of Cu granule (C 6 H 12 Cu 0.394 ) at a low density of 50 mg/cm 3 is heated by x-ray radiation emitted from the hohlraum. The breakout time of the radiation wave is measured by a three chromatic streaked x-ray spectrometer (TCS) that consists of a set of three imaging pinholes and an array of three transmission gratings coupled with an x-ray streak camera (XSC). At one shot, the simultaneous measurements of the drive source and the radiation transport at two energies (210 eV, 840 eV) through the foam have been made for the first time. The experimental results indicate that the time delays vary with photon energies. The radiation at energy 210 eV propagates at a lower velocity. Using TGS, the transmitting spectrum was measured, and the lower limit of the optical depth, which is more than 1, was obtained. The Mach number of the radiation wave is about 4. The radiation transport in the foam doped with Cu is diffusively supersonic and the diffusion approximation begins to be applicable. The experimental data were compared with the simulation of two-dimensional radiation hydrodynamics code and they reasonably agree.PACS: 52.50.Jm, 52.25.Nr

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“…Current simulations indicate that hohlraums used in ICF are optimized to drive a fusion capsule to ignition before reaching the x-ray production limits. On the other hand, many HED applications require a long sustained soft x-ray drive [6,7]. These experiments will approach the limits in T R -τ space, where T R is the hohlraum peak radiation temperature and τ is the time at which the internal hohlraum radiation flux will begin to drop or roll-over, even before the laser pulse terminates.…”

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confidence: 99%